Elevator



2 Sheets-Shed 1 ELEVATOR Filed Aug. 12, 1929 J. COCHlN Nov. 10, 1936.

ATTORNEYS. I

J. COCHIN Nov. 10, 1936.

ELEVATOR 2 Sheets-Sheet 2 Filed Aug. 12, 1929 INVENTOR.

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TTORNEYS.

Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE Application August 12,

Claims.

This invention relates to elevators of the type in which a compressible fluid, such as compressed air, is employed to transmit movement to an in compressible fluid for operating the device.

One object of the invention is to overcome the bad effects of leakage or lowering of pressure of the compressible fluid when the elevator is being maintained in raised position, with a heavy load for considerable periods. In such cases it is difficult or almost impossible to prevent a certain lowering of the air pressure, due to leakage, the effect of which has always been, in the case of prior devices of the hydro-pneumatic type, to cause the elevator (particularly when heavily loaded) to settle down, or even to drop a short distance with considerable suddenness.

In and by the prevent invention, provision is made whereby any such leakage of air or loss of pressure will in no wise affect the stability or position of the elevator in so far as concerns its ability to remain in fixed position.

A further object is to provide a self-contained device of the character mentioned, in which the reservoir for the incompressible fluid may be embodied within the ram, thus avoiding the necessity for separate tanks, and simplifying the installation of the entire device.

One form which my invention may assume is exemplified in the following description and illustrated in the accompanying drawings, in which Fig. 1 shows a vertical central sectional view of an elevator embodying my invention, especially designed for use in connection with the lifting of automobiles and the like;

Fig. 2 shows a horizontal central sectional view of the valve mechanism employed in connection therewith;

Fig. 3 shows a sectional view taken on the line III-III of Fig. 2;

Fig. 4 shows a sectional view taken on the line IV-IV of Fig. 2;

Fig. 5 shows a sectional view taken on the line VV of Fig. 2;

Fig. 6 shows a sectional View taken on the line VI-VI of Fig. 2.

The elevator mechanism as herein illustrated comprises a platform It! mounted on a ram H, which ram is herein illustrated as being in the form of a hollow piston containing a reservoir l I for incompressible fluid. The said ram is slidably mounted in a casing or housing 12, which contains a chamber l2 to receive incompressible fluid, so as to displace the ram.

Communicating with the interior of the reservoir is a pipe connection l3 for an incompressible fluid; and communicating with the chamber surrounding the ram is a second pipe connection M for incompressible fluid. These pipe connections communicate with each other through the valve mechanism indicated generally at I5, and

1929, Serial No. 385,420

are for the purpose of permitting the transfer of the incompressible fluid from the reservoir to the interior of the cylinder, and vice versa.

The reservoir has a conduit ll communicating with the interior thereof at the upper end. This conduit in turn communicates with the valve mechanism l5 and is for the purpose of admitting compressible fluid, such as compressed air, into the reservoir, so as to apply a pressure on the incompressible fluid which in turn causes a transfer of the incompressible fluid from the reservoir to the chamber surrounding the ram for raising the elevator. Y

The particular valve mechanism herein illustrated permits of the simultaneous operation of the valves for controlling the compressible fluid and the incompressible fluid, and is preferably mounted upon the platform I0, so as to move up and down therewith.

Air under pressure enters the valve mechanism through a pipe or flexible hose l8, into a chamber which is separated by a valve l 9 from the chamber which leads to the pipe ll. At one side thereof is an exhaust chamber for the compressible fluid, which is separated by a valve 2| from the chamber which leads to the said pipe ll. Both of these valves are of the bevel seated type and normally closed by spring means or fluid pressure and opened by slidable rods 22, which rods are depressed by a rocker arnr 23 so as to act alternately and not simultaneously. The rocker arm is actuated by a handle 24 placed in a position accessible t the operator.

It will be obvious from the foregoing that when valve I9 is opened, air under pressure will be admitted to the interior of the piston through the pipe l1, and when the rocker arm is pulled in the opposite direction, the valve 2| will be opened, allowing the air from the reservoir to be exhausted through the port 20.

Combined with this valve mechanism so as to operate in unison therewith, are valves for controlling the communication between the pipes l3 and M, as best shown in Fig. 4. This arrangement includes a chamber 24 communicating with the pipe line I 3 and separated from an outlet chamber 25 by a valve 26; also a chamber 21 communicating with the pipe line I4 and separated from said chamber 25 by a second valve 28. Both of these valves are of the bevel seated type, held normally closed by spring means or fluid pressure, and capable of being opened by sliding rods 29, said rods being alternately depressible by movement of the rocker arm 23.

The operation of the complete device is as follows:

Assuming that the hollow piston is in retracted position, as shown in Fig. 1, and is practically filled with an incompressible fluid, the operator will thrust forwardly on the handle 24, whereupon valves l9 and 26 will be opened. Air under pressure from a suitable source of supply (indicated at A) will then be admitted to the top of the piston, putting a pressure upon the incompressible fluid so as to force it through the pipe I3 and into the pipe [4. In this instance the incompressible fluid, after passing the valve 26 and entering the chamber 25, will be under sufficient pressure to depress the valve 28 and allow the passage of the fluid into the pipe I4. The incompressible fluid, upon entering the cylinder 12 below the piston, will cause the said piston to be raised to the desired height, within the limits of its movement. When the elevator has been raised to the desired height, the operator releases the handle 24, permitting valves [9 and 26 to close; whereupon the elevator will remain in its raised position. Any loss of air pressure through leakage or otherwise can not possibly permit the elevator to descend, inasmuch as the incompressible fluid remains in its transferred position and can not return, due to the closed positions of the valves 26 and 28.

When it is desired to lower the elevator, the handle is moved in the opposite direction, thus opening valves 2| and 28, whereupon the compressible fluid will be exhausted from the interior of the piston and the weight of the platform and piston will cause the compressible fluid to be transferred from the cylinder to the interior of the piston, said elevator descending gradually, in accordance with the degree of opening of the different valves.

From the foregoing it will be seen that I have provided an extremely safe and eflilcient elevator, and one which is ideally suited for purposes of raising heavy loads, in localities where a source of air under pressure is readily available, such as in garages.

It is obvious that many changes may be made in the construction and arrangement of the several parts of the device herein illustrated and described, the essential features being that of a ram, slidably mounted in a casing, which casing has a chamber for incompressible fluid to displace the ram, and a reservoir for incompressible fluid, which reservoir is preferably enclosed within the ram, and is so arranged as to transfer the incompressible fluid from the reservoir to the chamber surrounding the ram, there being a valved communication between the reservoir and said chamber, and a source of supply for compressible fluid under pressure, which latter has a valve communication with the reservoir, the valve mechanism being so arranged that when the admission of incompressible fluid to the reservoir is closed, there may also be effected a closure of the communication between said reservoir and the chamber surrounding the ram, whereby any leakage or loss of pressure in the compressible fluid will in no wise affect the condition of the incompressible fluid, and the ram will not be permitted to descend in any degree.

The reservoir might obviously be arranged separately from the ram, and while I do not disclaim such an arrangement, it is apparent that by embodying the reservoir within the ram, 9. simple, convenient, and economical installation can be made, so that the entire device is selfcontained except for the matter of air supply.

It is to be noted that the ram is capable of rotation within the casing or cylinder, and in case it is desired to revolve the platform (as in garage practice), a coupling 30 is shown on the hose l8, whereby, after the elevator is raised, the said hose may be uncoupled and the elevator left free to revolve. The rest of the connections, being all contained within the elevator, need not be disturbed.

As to the particular valve arrangement, there are many substitutes therefor, it being immaterial whether air and liquid valves are operated simultaneously or in succession, so long as the objects herein stated are attained; namely, to prevent sagging down of a heavily loaded platform over a period of time, as in garage practice, where it is desired to support in fixed and elevated position a heavy automobile or truck, while the attendant goes through the various operations of greasing, adjusting, and repairing.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An elevator comprising a fluid containing ram, a fluid containing casing surrounding the ram, normally closed fluid communication between said ram and casing, air control means carried by and movable with the elevator for introducing air under pressure or exhausting air from said ram, and means automatically operable to open the fluid communication between the ram and casing upon operation of said air control means.

2. An elevator, comprising a fluid containing ram, a fluid containing casing surrounding the ram, a conduit carried by the ram and forming fluid communication between the ram and casing, a second conduit for supplying air under pressure to the interior of the ram, and a single valve unit carried by and movable with the elevator and capable of operation to simultaneously control the flow of fluid through both of said conduits.

3. An elevator of the character described, comprising a ram casing, a hollow ram reciprocably mounted in said casing, a platform carried by said ram, a fluid conduit leading from the interior of the ram to a point in the plane of said platform and back through said ram to the casing beneath the ram, a second fluid conduit for the admission of a fluid to the interior of the ram, and a single valve unit disposed adjacent the platform for controlling the flow of fluid through both of said conduits.

4. An elevator, comprising a ram in the form of a hollow piston forming a reservoir for incompressible fluid, a casing surrounding the ram and forming a chamber for incompressible fluid to displace the ram, means for admitting compressible fluid to the reservoir and valve means carried by the ram and operable to simultaneously admit compressible fluid and permit the flow of said incompressible fluid from the reservoir to the casing.

5. An elevator, comprising a fluid containing ram, a fluid containing casing surrounding the ram, normally closed fluid communication between said ram and casing, control means carried by the ram for introducing air under pressure or exhausting air from said ram and valve means also carried by the ram and automatically operable to open the fluid communication between the ram and casing upon operation of said control means.

JOHN COCHIN. 

